Extending calibration-free force measurements to optically-trapped rod-shaped samples.
Extending calibration-free force measurements to optically-trapped rod-shaped samples.
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DOI：
10.1038/srep42960
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发表时间：
2017-02-21
影响因子：
4.6
通讯作者：
Martín-Badosa E
中科院分区：
文献类型：
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作者：
Català F;Marsà F;Montes-Usategui M;Farré A;Martín-Badosa E
光阱技术由于其非侵入性的性能和可用于定量研究，特别是对生物过程中所涉及的力的定量研究，已成为微尺度生物学研究的最佳选择。然而，可靠的力的测量取决于光学陷阱，这是不同的每个实验的校准，因此需要高度控制的局部变量，特别是被困对象的几何形状。许多生物样品具有细长的杆状形状，例如染色体、细胞内细胞器（例如，过氧化物酶体），膜小管，某些微藻，以及各种各样的细菌和寄生虫。这种类型的样品通常需要几个光学陷阱来稳定它们并使其在正确的空间方向上定向，这使得更难以确定所施加的总力。在这里，我们用全息光镊操纵玻璃微柱，并通过免校准直接检测光束动量来精确测量阻力。我们的结果和细长体流体动力学理论计算之间的协议表明这种力传感方法在研究长期，杆状标本的潜力。
Optical trapping has become an optimal choice for biological research at the microscale due to its non-invasive performance and accessibility for quantitative studies, especially on the forces involved in biological processes. However, reliable force measurements depend on the calibration of the optical traps, which is different for each experiment and hence requires high control of the local variables, especially of the trapped object geometry. Many biological samples have an elongated, rod-like shape, such as chromosomes, intracellular organelles (e.g., peroxisomes), membrane tubules, certain microalgae, and a wide variety of bacteria and parasites. This type of samples often requires several optical traps to stabilize and orient them in the correct spatial direction, making it more difficult to determine the total force applied. Here, we manipulate glass microcylinders with holographic optical tweezers and show the accurate measurement of drag forces by calibration-free direct detection of beam momentum. The agreement between our results and slender-body hydrodynamic theoretical calculations indicates potential for this force-sensing method in studying protracted, rod-shaped specimens.